Bridgmanite
CaGeO3
third-order Birch-Murnaghan · Original · 1999
V₀
206.49
ų
Unit cell
K₀
194
GPa
Isothermal
K′
6.100
dimensionless
Volume (V₀)
| Value | Unit | Basis | Z |
|---|---|---|---|
| 206.49 | ų | Unit cell | — |
Reported value and unit are preserved as extracted. Z (formula units per cell) is not stored yet, so molar ↔ ų/f.u. conversion is not applied automatically.
Composition
| Oxide | Molar |
|---|---|
| CaO | 1 |
| GeO2 | 1 |
Formula: CaGeO3
Conditions & method
- Tref
- —
- Pref
- 0.000 GPa
- Structure
- orthorhombic perovskite (Pbnm/Pnma)
- Method
- experiment (XRD / DAC / multianvil compression)high-pressure single-crystal X-ray diffraction (diamond-anvil cell, quartz internal pressure standard), weighted-least-squares fit to P-V data
- Sample
- single crystals synthesized at 10 GPa and 1000 °C in a multi-anvil press at the Bayerisches Geoinstitut from CaGeO3 wollastonite
Source
- Paper
- Compression of CaTiO 3 and CaGeO 3 perovskites
- Authors
- Nancy L. Ross; R. J. Angel
- DOI
- 10.2138/am-1999-0309
- Year
- 1999
- Journal
- American Mineralogist
- Origin
- Original (measured or fitted in the source paper)
Evidence from the paper
For CaGeO3, this analysis yields V0 = 206.490 ± 0.017 ų, K_T.0 = 194.0 ± 2.1 GPa, and K' = 6.1 ± 0.5 with a χ²w = 1.1 and ΔPmax = 0.03 GPa.
Additional notes
P max GPa
8.553
measured ambient unit cell volume
206.484(18) ų at 0.0001 GPa (Table 1)
chi2 w
1.1
delta P max
0.03 GPa
axial moduli
Ka = 195 ± 5 GPa (K'a = 6.9 ± 1.2), Kb = 188 ± 4 GPa (K'b = 5.0 ± 0.9), Kc = 204 ± 3 GPa (K'c = 5.3 ± 0.6), from linear Murnaghan EoS fits to axes
comparison ultrasonic Ks
Ks = 198 ± 15 GPa (Liebermann et al. 1977)
lower mantle relevance
analogue framed in context of lower-mantle silicate perovskites MgSiO3 and CaSiO3